| use std::fmt::{self, Debug}; |
| use std::marker::PhantomData; |
| use std::path::Path; |
| |
| /// Build configuration. See [CFG]. |
| pub struct Cfg<'a> { |
| pub include_prefix: &'a str, |
| // Not implemented yet. https://github.com/dtolnay/cxx/issues/417 |
| #[doc(hidden)] |
| pub exported_header_dirs: Vec<&'a Path>, |
| #[doc(hidden)] |
| pub exported_header_prefixes: Vec<&'a str>, |
| #[doc(hidden)] |
| pub exported_header_links: Vec<&'a str>, |
| marker: PhantomData<*const ()>, // !Send + !Sync |
| } |
| |
| /// Global configuration of the current build. |
| /// |
| /// <br> |
| /// |
| /// ## **`CFG.include_prefix`** |
| /// |
| /// Presently the only exposed configuration is the `include_prefix`, the prefix |
| /// at which C++ code from your crate as well as directly dependent crates can |
| /// access the code generated during this build. |
| /// |
| /// By default, the `include_prefix` is equal to the name of the current crate. |
| /// That means if our crate is called `demo` and has Rust source files in a |
| /// *src/* directory and maybe some handwritten C++ header files in an |
| /// *include/* directory, then the current crate as well as downstream crates |
| /// might include them as follows: |
| /// |
| /// ``` |
| /// # const _: &str = stringify! { |
| /// // include one of the handwritten headers: |
| /// #include "demo/include/wow.h" |
| /// |
| /// // include a header generated from Rust cxx::bridge: |
| /// #include "demo/src/lib.rs.h" |
| /// # }; |
| /// ``` |
| /// |
| /// By modifying `CFG.include_prefix` we can substitute a prefix that is |
| /// different from the crate name if desired. Here we'll change it to |
| /// `"path/to"` which will make import paths take the form |
| /// `"path/to/include/wow.h"` and `"path/to/src/lib.rs.h"`. |
| /// |
| /// ```no_run |
| /// // build.rs |
| /// |
| /// use cxx_build::CFG; |
| /// |
| /// fn main() { |
| /// CFG.include_prefix = "path/to"; |
| /// |
| /// cxx_build::bridge("src/lib.rs") |
| /// .file("src/demo.cc") // probably contains `#include "path/to/src/lib.rs.h"` |
| /// /* ... */ |
| /// .compile("demo"); |
| /// } |
| /// ``` |
| /// |
| /// Note that cross-crate imports are only made available between **direct |
| /// dependencies**. Another crate must directly depend on your crate in order to |
| /// #include its headers; a transitive dependency is not sufficient. |
| /// Additionally, headers from a direct dependency are only importable if the |
| /// dependency's Cargo.toml manifest contains a `links` key. If not, its headers |
| /// will not be importable from outside of the same crate. |
| #[cfg(doc)] |
| pub static mut CFG: Cfg = Cfg { |
| include_prefix: "", |
| exported_header_dirs: Vec::new(), |
| exported_header_prefixes: Vec::new(), |
| exported_header_links: Vec::new(), |
| marker: PhantomData, |
| }; |
| |
| impl<'a> Debug for Cfg<'a> { |
| fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { |
| formatter |
| .debug_struct("Cfg") |
| .field("include_prefix", &self.include_prefix) |
| .finish() |
| } |
| } |
| |
| #[cfg(not(doc))] |
| pub use self::r#impl::Cfg::CFG; |
| |
| #[cfg(not(doc))] |
| mod r#impl { |
| use crate::intern::{intern, InternedString}; |
| use lazy_static::lazy_static; |
| use std::cell::RefCell; |
| use std::collections::HashMap; |
| use std::fmt::{self, Debug}; |
| use std::marker::PhantomData; |
| use std::ops::{Deref, DerefMut}; |
| use std::path::Path; |
| use std::sync::{PoisonError, RwLock}; |
| |
| struct CurrentCfg { |
| include_prefix: InternedString, |
| exported_header_dirs: Vec<InternedString>, |
| exported_header_prefixes: Vec<InternedString>, |
| exported_header_links: Vec<InternedString>, |
| } |
| |
| impl CurrentCfg { |
| fn default() -> Self { |
| let include_prefix = crate::env_os("CARGO_PKG_NAME") |
| .map(|pkg| intern(&pkg.to_string_lossy())) |
| .unwrap_or_default(); |
| let exported_header_dirs = Vec::new(); |
| let exported_header_prefixes = Vec::new(); |
| let exported_header_links = Vec::new(); |
| CurrentCfg { |
| include_prefix, |
| exported_header_dirs, |
| exported_header_prefixes, |
| exported_header_links, |
| } |
| } |
| } |
| |
| lazy_static! { |
| static ref CURRENT: RwLock<CurrentCfg> = RwLock::new(CurrentCfg::default()); |
| } |
| |
| thread_local! { |
| // FIXME: If https://github.com/rust-lang/rust/issues/77425 is resolved, |
| // we can delete this thread local side table and instead make each CFG |
| // instance directly own the associated super::Cfg. |
| // |
| // #[allow(const_item_mutation)] |
| // pub const CFG: Cfg = Cfg { |
| // cfg: AtomicPtr::new(ptr::null_mut()), |
| // }; |
| // pub struct Cfg { |
| // cfg: AtomicPtr<super::Cfg>, |
| // } |
| // |
| static CONST_DEREFS: RefCell<HashMap<Handle, Box<super::Cfg<'static>>>> = RefCell::default(); |
| } |
| |
| #[derive(Eq, PartialEq, Hash)] |
| struct Handle(*const Cfg<'static>); |
| |
| impl<'a> Cfg<'a> { |
| fn current() -> super::Cfg<'a> { |
| let current = CURRENT.read().unwrap_or_else(PoisonError::into_inner); |
| let include_prefix = current.include_prefix.str(); |
| let exported_header_dirs = current |
| .exported_header_dirs |
| .iter() |
| .copied() |
| .map(InternedString::str) |
| .map(Path::new) |
| .collect(); |
| let exported_header_prefixes = current |
| .exported_header_prefixes |
| .iter() |
| .copied() |
| .map(InternedString::str) |
| .collect(); |
| let exported_header_links = current |
| .exported_header_links |
| .iter() |
| .copied() |
| .map(InternedString::str) |
| .collect(); |
| super::Cfg { |
| include_prefix, |
| exported_header_dirs, |
| exported_header_prefixes, |
| exported_header_links, |
| marker: PhantomData, |
| } |
| } |
| |
| const fn handle(self: &Cfg<'a>) -> Handle { |
| Handle(<*const Cfg>::cast(self)) |
| } |
| } |
| |
| // Since super::Cfg is !Send and !Sync, all Cfg are thread local and will |
| // drop on the same thread where they were created. |
| pub enum Cfg<'a> { |
| Mut(super::Cfg<'a>), |
| CFG, |
| } |
| |
| impl<'a> Debug for Cfg<'a> { |
| fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { |
| if let Cfg::Mut(cfg) = self { |
| Debug::fmt(cfg, formatter) |
| } else { |
| Debug::fmt(&Cfg::current(), formatter) |
| } |
| } |
| } |
| |
| impl<'a> Deref for Cfg<'a> { |
| type Target = super::Cfg<'a>; |
| |
| fn deref(&self) -> &Self::Target { |
| if let Cfg::Mut(cfg) = self { |
| cfg |
| } else { |
| let cfg = CONST_DEREFS.with(|derefs| -> *mut super::Cfg { |
| &mut **derefs |
| .borrow_mut() |
| .entry(self.handle()) |
| .or_insert_with(|| Box::new(Cfg::current())) |
| }); |
| unsafe { &mut *cfg } |
| } |
| } |
| } |
| |
| impl<'a> DerefMut for Cfg<'a> { |
| fn deref_mut(&mut self) -> &mut Self::Target { |
| if let Cfg::CFG = self { |
| CONST_DEREFS.with(|derefs| derefs.borrow_mut().remove(&self.handle())); |
| *self = Cfg::Mut(Cfg::current()); |
| } |
| match self { |
| Cfg::Mut(cfg) => cfg, |
| Cfg::CFG => unreachable!(), |
| } |
| } |
| } |
| |
| impl<'a> Drop for Cfg<'a> { |
| fn drop(&mut self) { |
| if let Cfg::Mut(cfg) = self { |
| let mut current = CURRENT.write().unwrap_or_else(PoisonError::into_inner); |
| current.include_prefix = intern(cfg.include_prefix); |
| current.exported_header_dirs = cfg |
| .exported_header_dirs |
| .iter() |
| .copied() |
| .map(|path| intern(&path.to_string_lossy())) |
| .collect(); |
| current.exported_header_prefixes = cfg |
| .exported_header_prefixes |
| .iter() |
| .copied() |
| .map(intern) |
| .collect(); |
| current.exported_header_links = cfg |
| .exported_header_links |
| .iter() |
| .copied() |
| .map(intern) |
| .collect(); |
| } else { |
| CONST_DEREFS.with(|derefs| derefs.borrow_mut().remove(&self.handle())); |
| } |
| } |
| } |
| } |